A US woman who shot and killed her husband and two adult children before taking her own life is thought to have committed the shocking crime as a result of being ostracised from the religion she was raised in.

A federal judge sentenced a former Arkansas judge Wednesday to five years in prison — a stiffer punishment than prosecutors recommended — after he admitted giving young male defendants lighter sentences in return for personal benefits that included sexual favours.

Every time I tell a mate I’m doing a story on cryptocurrency, they invariably ask me the same two questions: should they invest their own hard-earned money, and which cryptocurrency will get them a Lamborghini/yacht/island quickest?

In a 60 Minutes online exclusive, reporter Liz Hayes quizzed Australian Prime Minister Malcolm Turnbull on his relationship with the unpredictable Twitter aficionado and US president Donald Trump ahead of their meeting at the White House Friday.

Russia warned before US attack in Syria

The US military gave Russian forces advanced notice of its strikes on a Syrian air base and did not hit sections of the base where the Russians were believed to be present, Pentagon spokesman Captain Jeff Davis said on Thursday.

Davis, briefing reporters on the operation, said the US military had "multiple" conversations with Russian forces on Thursday before the strike, using a line of communication that had previously been established to prevent an accidental clash in Syria during the fight against Islamic State.

Some 50 Tomahawk missiles were launched from US Navy warships in the eastern Mediterranean Sea, striking multiple targets - including the airstrip, aircraft and fuel stations - on the Shayrat Air Base in the early hours of Friday (local Syria time).

The action was ordered by US President Donald Trump after he blamed Syrian President Bashar al-Assad for this week's gruesome chemical attack which killed at least 70 people in the town of Khan Sheikhoun.